(17)In order to address some of the uncertainties inherent in setting national emission reduction commitments, the revised Gothenburg Protocol includes flexibilities which should be incorporated into this Directive. In particular, the revised Gothenburg Protocol establishes a mechanism to adjust national emission inventories and to average national annual emissions for a maximum of three years where certain conditions are met. In addition, flexibilities should be laid down in this Directive where it imposes a reduction commitment which exceeds the cost-effective reduction identified in TSAP 16 and also to assist Member States in case of sudden and exceptional events related to energy generation or supply provided that specific conditions are met. The use of those flexibilities should be monitored by the Commission while taking into account guidance developed under the LRTAP Convention. For the purposes of assessing applications for adjustments, the emission reduction commitments for the period between 2020 and 2029 should be considered to have been set on 4 May 2012, the date when the Gothenburg Protocol was revised.